Dairy Science Department
BS in Dairy Science
The objective of the study was to determine the factors involved in the reduction of carbon to nitrogen ratio in composted separated solids. A single compost windrow was laid on a 6,000 jersey cow dairy farm located in Madera County. Samples were obtained from six separate positions on the pile, every other day. Direct pile measurements on the date of sampling included pile temperature (surface and core), height, width and curvature. Samples were removed from the windrow during each sampling meeting to determine the percent dry matter content. The collected samples were sent out to Denele Analytical Inc. to determine bi-weekly carbon to nitrogen ratios on pile positions one, three and six, both surface and core. Factors such as rotation frequency, wind speed, outside temperature, humidity and rain were noted on all sample dates. Statistical analysis was performed using the SAS GLMSELECT procedure to identify the significant factors in the reduction of carbon to nitrogen ratio. Fifteen independent variables/factors were run through SAS and four independent variables were found to impact the composting process. Pile area, temperature at the pile core, date of sampling and wind speed were the factors that changed the dependent variable of carbon to nitrogen ratio. Further research is needed to determine if additional factors can impact the composting process and to expand the number of observations of C/N ratios.